Assembly knowledge of energy-saving power distribution cabinets

1. General

The content and requirements of the assembly of low-voltage power distribution products are applicable to the assembly process of various types of low-voltage power distribution products such as switchgear, power box, distribution box, control panel, platform and busbar plug-in box.

2, equipment and tools

2.1 Equipment: bending machine, 50KVA test transformer, balanced bridge, tin furnace, bench drill and so on.

2.2 Tools: screwdriver, needle-nosed pliers, wire stripper, crimping pliers, multimeter, megohmmeter, wrench, steel tape measure, steel ruler, vernier caliper, feeler gauge, coating thickness gauge, etc.

3, assembly specifications

3.1 Before the assembly of the product, the following items should be inspected one by one to prepare the process.

3.1.1 The structure shall comply with the requirements of the product structure of the model, and the product shall have a fixed mounting hole.

3.1.2 The door should be able to flexibly rotate in an angle greater than 90°. The door should not damage the paint film during the rotation process, and the electrical components should not be subjected to impact. There should be no obvious shaking after the door is locked. Inspection method: The hand lock is gently pushed and pulled, and the movement amount does not exceed 2mm.

3.1.3 Inspection of the gap between the door and the door and the door and the frame: the gap between the door and the door is less than 1000mm for 1mm, greater than 1000mm for 1.5mm, and the gap between the door and the door frame is less than 1000mm. It is 2mm, and it is 2.5mm larger than 1000mm.

3.1.4 The welding of the shell should be firm, the weld should be smooth and uniform, and there should be no welding, cracks, undercuts, slag splashes, pores, etc. The weld skin should be cleaned.

3.1.5 After the surface treatment of the shell, the surface of the paint film should be full, the color is clear, the color is uniform, smooth and smooth, and the brush marks, wrinkles, pinholes, blistering, scars, marks, fingerprints, trimming marks and Defects such as mechanical impurities.

3.1.6 The plating of all plating parts on the product (including the plating and fasteners of the plating parts of the components themselves) shall not cause peeling, falling off, blackening or rusting.

3.2 Component selection and installation

3.2.1 The electrical components and materials selected in the product must meet the requirements of the certified product and the customer's drawings. Without prejudice to the inherent quality requirements of the product, the customer's consent and relevant approval can be obtained for the substitution within the scope of the certification. .

3.2.2 Components must be qualified products produced by manufacturers that have obtained compulsory product certification, and non-certified products may not be used.

3.2.3 All indicators and button colors on the product shall comply with the provisions of GB/T 4025-2003, or in accordance with the schematic or wiring diagram.

3.2.4 All components shall be installed and used according to the installation and use conditions specified in their manufacture. The inclination of the components shall not exceed 5°. It shall be ensured that the arc of the switch does not cause harm to the operator. Manually operated components and operating mechanisms shall be flexible. No jamming.

3.2.5 All components should be firmly fixed on the skeleton or bracket. Each component should be marked with a conspicuous symbol. The symbol or code used must be consistent with the schematic or wiring diagram.

3.2.6 When the end of the auxiliary circuit wire is connected with the component, the wire number tube must be worn. The label should be correct, firm and firm, and have permanent adhesion. The label must be consistent with the wiring icon number.

3.2.7 The components to be installed shall be easy to operate, and shall not be obstructed by space during operation, and shall not touch the charged body.

3.2.8 The terminals of electrical components, units and external conductors installed on the same bracket (mounting plate, mounting frame) shall be arranged so that they are easily accessible during installation, wiring, maintenance and replacement. In particular, the external terminal block shall be located at least 0.2 m above the base surface of the ground-mounted equipment and the terminal shall be installed so that the cable is easily connected to it. Components that must be adjusted and reset within the plant should be easily accessible. For ground-mounted equipment, the indicator that is observed by the operator should not be installed 2m above the base surface of the plant. Operating devices, such as handles, buttons, etc., should be installed at an easy-to-operate height; their centerline should generally not be 2m above the base surface of the plant.

3.2.9 Switching devices and components shall be installed in accordance with the manufacturer's instructions (use conditions, arcing distance, moving distance of the arc chute, etc.) to meet the requirements of the electrical component product specification, for example, to meet the arcing distance, clearance and climb Electrical distance requirements.

3.2.10 to ensure the production and installation distance of the first and second lines, the heating element should be placed above the switchgear and should be kept at a certain distance from the insulated wire.

3.2.11 The assembly of the same product in the same batch shall be consistent.

3.2.12 Components or accessories are mounted on the corresponding bracket or mounting plate, and then the bracket or mounting plate is mounted on the cabinet; or directly mounted on the cabinet. Accurately measure and adjust the installation position and tighten it. Do not hit heavy parts and electrical components during adjustment.

3.2.13 The protective layer of fasteners and metal parts used for assembly shall not fall off or rust. The screw selection is to match the hole in the component. After fastening, the screw exposes the nut 3-5 pitches.

3.2.14 When considering the grounding continuity, the grounding continuity should be fully considered. If any two metal parts in the box are connected by bolts, the grounding washer of the corresponding specification should be used for the insulation layer, and the tooth surface of the grounding washer should be in contact with the surface of the component to draw Broken insulation.

3.2.15 When installing components that are easily damaged by vibration, a rubber pad should be added between the components and the mounting plate to absorb vibration.

3.2.16 For components with operating handles, they should be adjusted in place and must not be jammed.

3.2.17 After assembly, the fasteners, fuses, switch covers, handles, arc-extinguishing covers, etc., which have been removed from the components, are all installed. 12. Tighten the bolts on the busbars and components reserved for customer wiring.

3.2.18 Various protective plates shall be installed in place.

3.2.20 The installation requirements for various components are as follows:

3.2.20.1 Frame type low voltage circuit breaker

(1) The frame type low-voltage circuit breaker is relatively heavy, generally should be placed under the back of the screen, and the angle steel with large mechanical strength should be used as the mounting plate.

(2) Install the switch body in the base of the switch cabinet according to the requirements of the instruction manual, shake the operation handle so that the body can slide back and forth in the guide rail, and the sliding contact of the three-phase main contact of the switch and the auxiliary circuit can be connected with Disconnect, so that the three positions of connection, test and disconnection meet the requirements of the manual.

(3) It should be energized to check whether the trip units are flexible, and whether the closing and opening are flexible and reliable.

3.2.20.2 Plastic case type low voltage circuit breaker.

(1) The plastic case type low-voltage circuit breaker can be installed after opening the outer casing. To prevent mechanical damage of the outer casing, its wiring is realized by the connecting screw. Pay attention to the creepage distance between the connecting screw and the screen hole to avoid insufficient insulation strength. Short circuit.